Lel don't be stupid OP. Ninjutsu in it's modern form (with handseals and shit) not existing during Hagoromo's time doesn't mean that they can't fight, it means that they fight without the need for handseals. Taijutsu? Irrelevant on this level, especially since basic fighting skills are all that they need to rape pretty much 99% of the strongest people in this series in Taijutsu.